Mini inhibition

During an action potential neurons release a huge bolus of neurotransmitter, which can alter protein synthesis in the receiving cell and reshape synapses during learning. But neurons also release single packets of neurotransmitter in a background dribble that has been largely ignored. Now, Michael Sutton, Erin Schuman, and colleagues (Caltech, Pasadena, CA) have found that these “minis” inhibit translation in dendrites. This may help neurons to start from a lower basal level, thus making the increase in translation after action potentials more dramatic.

The Caltech team “stumbled upon [the effect] by accident,” says Sutton. “The idea was to remove all synaptic activity and add it back,” while looking for changes in dendritic protein synthesis. Inhibition of action potentials reduced protein synthesis, but inhibition of both action potentials and minis led to an increase in protein...